I'm really informed about Sigma... and not only, adri.
I do not care if a lens "outperform" an another lens. I care much about rendering consistency. Again "outperform" is a bold statement for charts. Sigma lenses give more performances in only one area : resolution. And again, if we speak about Sony... latest sony lenses have nothing to envy to sigma. The latest Canon L 35mm have nothing to envy to Sigma. The very light Zeiss 35f2 have nothing to envy to Sigma. Finally, the Nikon 35f1.4 is simply a pro choice for the very reason I stated : Rendering consistency.
I understand someone on a budget might skip the brand lenses offering and go full sigma art. But the after sale service is far from Nikon service I'm afraid and that's not gonna change tomorrow.
Adapting a lens x on a camera y is nice (for the whole market and user wallet) but often come with drawbacks. Professionals do it with only few lenses, often the canon 17 TS and other very useful professional lenses. The rest are hobbyist with lots of lenses up their shelves and lot of time for forums and social media's.
I never been a third party or alternative lens photographer.
My comment above was more toward Sigma cameras than Sigma lenses, by the way. This is a good thing to have such performance from a third party lens maker. It push other company to refresh some optics BUT is this the most important ? Resolution ?
I do not think so.